AbstractEcosystem service and human activity assessment are essential for effective natural resources allocation; however, these were seldom researched in arid region. This study used the theory proposed by Millennium Ecosystem Assessment to analyse ecosystem services provided by the floodplain forest in the lower reaches of the Tarim River. Results showed the following: (a) In the research area, the ecosystem service values of approximately US$216.78 × 108 occurring from 1972 to 2015 showed a decreasing trend; (b) the total ecosystem service values for floodplain forest and water area for all land use and land cover types accounted for 87.43% of the total value in the research area, and water supply, biodiversity protection, and waste treatment accounted for 55% of the total function values—these were the highest service values; (c) this research showed that the estimated ecosystem service values of research area were inelastic to value coefficients. This study showed that future work should allow land use and Ecological Water Conveyance Project to follow with rigorous environmental impact analyses. These analyses will be crucial to maintain the stability and sustainable development in the lower reaches of the Tarim River and also can provide references for research in the arid regions of Northwest China and Central Asia.